We found a spot a little ways in. You have to drive about 1/4 mile in past the apache stables before camping is allowed. The first several spots were already taken. I imagine this is pretty normal for summer but many campgrounds being closed due to covid probably doesn’t help. The spot was fairly flat and no one nearby but we could hear people in the distance (other boondockers) until around midnight. The biggest problem with our spot was it was pretty close to the road and people in trucks flew by every so often pretty late into the night. Otherwise it was great. Only about 7 minutes from our spot to the grand canyon entrance which you can’t really beat. We saw a female elk in the morning as we left the spot towards gc. Would definitely stay again on a gc visit.
There were lots of people there already but if you keep driving there was still lots of open spots further in
Another free option in the forest just outside Grand Canyon. Many people are also camping, but just drive down until you see an open previously-occupied area. Note that you'll have to go back through the Grand canyon entrance in the morning.